WO2004089803A1

WO2004089803A1 - Mining skip

Info

Publication number: WO2004089803A1
Application number: PCT/ZA2004/000036
Authority: WO
Inventors: Berend Jan Werkman
Original assignee: Berend Jan Werkman
Priority date: 2003-04-11
Filing date: 2004-03-29
Publication date: 2004-10-21

Abstract

A load transporting carrier in the form of a mining skip (10) comprises a carrier body in the form of a skip body (12) formed with planar sidewalls (16) extending between curved corners (18). The skip body (12) is strengthened against outward urging once exposed to a load by a plurality of circumferentially welded rib formations (20) secured along the inner wall of the body (12). The welds between the panels (34) and the corner formations (38) of the skip body (12) and between the corner and linear sections (40), (42) of the rib formations (20) are located in the regions of contra flexure of the skip body (12) to limit the effect of bodily exerted stresses during use of the skip (10).

Description

(1) TITLE OF THE INVENTION MINING SKIP

(2) BACKGROUND TO THE INVENTION

Mining skips or other similar equipment are used along areas of lateral limited spacing as defined by the shaft along which they move. It is obviously of great importance to optimise the ability of such skips to handle material transported along. Of particular importance is the ability to safely lift as much material as possible per charge. To this end it is thus important to reduce the weight of the skip to as low as possible without compromising its strength inclusive of making optimum use of the cross sectional area of a shaft. (3) FIELD OF THE INVENTION

This invention relates to a load transporting carrier employable for transferring a load that has the effect of exerting an outward force on the side walls of the carrier body during its operative use and to a method of at least strengthening a load transporting carrier conventionally being formed with planar side walls that are so exposed to outwardly urging load forces during operative use. Although not so limited the invention finds useful application in the field of mining skips.

(4) PRIOR ART DESCRIPTION

Mining and other types of skips displaceable along shafts are commonly known in the art.

Conventionally the walls of such skips are manufactured to be of substantial thickness to ensure a body of adequate strength to enable the safe transport of material. The material used for such manufacturing is normally of high density to achieve the desired strength.

Being thick walled reduces the optimum use of the cross sectional area of a shaft or the like.

These factors, amongst others, limit the capability of the skip to transport an optimum weight of material per charge as the weight of the skip naturally forms part of the overall weight that must be lifted. It is, amongst others, an object of this invention to address this situation. (5) BRIEF DESCRIPTION OF THE DRAWING

The invention is now described, by way of example, with reference to the accompanying drawings. In the drawings

Figure 1 shows a load transporting cage, according to the invention, in the form of a mining skip in partly cut away side elevation,

Figure 2 shows the skip in end elevation,

Figure 3 shows the core part of the skip in more detailed open sided view,

Figure 4 shows the skip along section line A-A in figure 1 though omitting the detail of the bottom end of the skip, Figure 5 shows a detail of the part of the wall of the skip as appropriately strengthened, in plan view,

Figure 6 shows the detail of figure 5 along section line B-B,

Figure 7 shows the detail of figure 5 along section line C-C,

Figure 8 shows the detail of figure 5 along section line D-D, Figure 9 shows in detailed overhead view the layout of the charge aperture of the skip, and

Figure 10 diagrammatically shows the opening and closing mechanism of and steps for opening and closing the discharge door of the skip.

(6) DETAILED DESCRIPTION OF THE DRAWINGS

Referring to figures 1 to 4 of the drawings a load transporting carrier, according to the invention, in the form of a mining skip is generally indicated by reference numeral 10.

The skip 10 comprises a carrier body in the form of skip body 12 of generally rectangular end profile encompassing a loading zone 14 with the skip body 12 being formed with planar side walls 16 extending between curved skip body corners 18 and being strengthened against outward urging once exposed to a load by a carrier body sidewall outward displacement limiting and strengthening rib formation layout in the form of a plurality of integrally secured rib formations 20 integrally secured by being welded to the inside surface of the skip body 12 to circumferentially extend in planes that extend transverse to the axis of displacement 22 of the skip 10.

The skip 10 is fitted with an overhead charging opening 24 while its discharge opening 26 is reopenably closable by a hingedly mounted door 28 of which the opening and closure mechanism is discussed in more detail below. The skip 10 is naturally also fitted with conventional connection means inclusive of a connecting assembly 29 that is connected via a cross member 30 to a bridle 32 surrounded by the skip body 12. The skip 10 is thus operatively installable via conventional winder ropes (not shown) found along a shaft and used for its displacement.

As more clearly shown in figure 4 the skip body 12 is constituted from panels 34 integrally secured by way of seam welds 36 to curvedly formed skip body corner formations 38. The welds 36 consequently extend in the direction of the axis 22. To limit the exertion of stress along locations of reduced skip body strength once the skip 10 is used under load conditions, as found along such welds 36, the corner formations 38 and the panels 34 are dimensioned to result in the welds 36 extending in the regions of contra flexure of the wall of the body 12. These are thus the positions where the flexing of the side walls 16 become inverted causing regions of reduced bending stress along the body 12. These regions are typically found at locations in the order of a distance of 20% of the full width of a side wall 16 from the corners of the skip body 12 at least when of rectangular end profile.

Referring also to figures 5 to 8 the rib formations 20 thus extend circumferentially along the inside of the side walls 16 and through the corners sections 18 of the body 12. The formations 20 are integrally secured to the skip body 12 by being welded thereto by way of circumferentially extending linear seam welds, as discussed in more detail below. Such technique of securing does not effectively contribute to the formation of zones of reduced skip wall endurance, as normally brought about by applying a welding effect to the material of the skip body 12, owing to the direction of such welds lying along and thus flexing in conjunction with the flexing plane of a side wall 16 on its outward flexing once put under stress on the skip 10 being charged. A weld that lies otherwise and especially down the flexing plane, as conventionally found in the fitting of strengthening means to a skip body, is more susceptible to contributing to skip body metal fatigue. This results in the quicker deterioration as caused by cracking or even tearing along zones of reduced wall endurance and consequent shorter skip life.

Each rib formation 20 is constituted from four arcuately formed corner sections 40 and four linear sections 42 that link the corner sections 40 owing to their being integrally end on secured by way of welding to opposite corner sections 40. The linear and corner sections 40, 42 respectively are channel shaped with the corner sections naturally extending arcuately. The corner sections 40, as curved to snugly fit into the curved corner formations 38 of the skip body 12, extend by way of linear portion 44 some distance along the side walls of the body 12. The lengths of the portions 44 are suitably selected to result in their locations of welded inter-securing to the linear sections 42 lying adjacent the positions of contra flexure of the side walls of the body 12. As at least part of the direction of welded inter-securing 43 between the corner sections 40 and the linear sections 42 also extend in the direction of the axis 22, lying so adjacent the positions of contra flexing has the effect of also limiting exposure of the inter-securing welding to bending stress that is brought about by outward flexing of the sidewalls 16 of the skip body 12 once the skip10 is use.

As more clearly shown in figures 6 and 7 the linear sections 42 each consists of longitudinal side flanges 42.1 connected by a web 42.2. The sections 42 are thus secured along welds 46 that extend transverse to the axis 22 of the skip 10 to the wall of the skip body 12 for the reason as already discussed.

In referring specifically to figure 8 the end profiles of the corner sections 40 match that of the linear sections 42 though each naturally extending through a curve. In addition to the opposite side flanges 40.1 the corner sections 40 are also formed with intermediate strengthening ribs 40.2 that extend between the web 40.3 of each section 40 and the inner face of the sidewall 16. The flanges 40.1 and the rib 40.2 are secured to the skip sidewall 16 along welds 48 also extending transverse to the axis 22. To further strengthen the corner sections 40, as they are subject to large bending stresses during use of the skip 10, and referring particularly to figure 5 their inner radii 50 are of generally the same magnitude as the outer radii 52. The radii 50 and 52 being so similar has the effect that the depth 54 of each corner section 40 progressively increases from the opposite locations of commencement of curvature formation 56 towards its centre position 58. As a useful design parameter the outer radius 52 of each corner section 40 is in the order of ten times the thickness of the wall of the skip body 12. In specifically referring to figures 6 to 8 the various parts of the rib formations 20 are formed with oblique overhead sections in the form of deflecting strips 60 that slant inward and downward to counteract blocking of material within the loading zone 14 once the skip 10 is in use. The strips 60 are naturally also welded to the skip body 12 in the same way as the corner and linear sections 40 and 42 respectively. While the rib formations 20 are naturally exposed to large abrasion effects during use of the skip 10 it is useful to protect the strips 60 and the webs 40.3, 42.2 there against. To this end the strips 60 are clad with liners 62 that are usefully replaceable fitted to the strip 60 by being bolted via the sidewall 16 of the skip 10 to the strips 60. The lower end lips 62.1 of the liners 62 can conveniently overhang the strips 60 further protecting the webs 40.3 and 42.2. Referring in particular again to figures 1 and 3 it is clear that the disposition of the charging opening 24 of the skip 10 relative to the loading zone 14 has the result that the linear sections 42.3 situated along the opposite wall of the skip body 12 are exposed to extensive impact during charging of the skip 10. As an additional protection while also in particular referring to figure 6 these linear sections can be fitted with resilient impact absorbing buffers 64 that overhang the liners 62. The buffers 64 are typically in the form of resilient layer material 64.1 sandwiched between inner and outer protecting liners 64.2. The buffers 64 are conveniently bolted to the skip body 16 enabling their replacement.

Referring more particularly to figure 3 the skip 10 is formed with a discharge zone 66 of reduced cross sectional area. This is achieved by causing an extension of the webs 40.3, 42.2 of the second lowest rib formation 20.1 to form the wall of the bottom section 16.1 of the skip body 16. Such narrowing of only the bottom has the advantage that the discharge door 28 which has to be larger than the discharge opening 26 promoting a spillage free discharge of the skip 10 when is use. This promotes utilising the skip 10 to its maximum capacity along its constricted zone of displacement such as a mining shaft.

Referring again to figure 1 and also to figure 9 the charging opening 24 is dimensioned to be narrower than the side walls while its lower section is formed with funnel defining flanges 68. This directs the charging effect towards the centre of the loading zone 14 that in turn reduces stiffener wear. Referring also to figure 10 the opening and closing mechanism of the discharge door 28 of the skip is generally indicated by reference numeral 70. The mechanism 70 involves guide assembly engaging means in the form of displacement rollers 72 for the lateral displacement of the skip 10 as such and a cam and follower arrangement 74 for the opening and closure of the door 28. Use of the mechanism 70 involves the pendulous displacement of the skip 10 in the direction of arrow 76. It is consequently suspended from the cross member 30 forming part of the bridle 32. The skip 10 is thus formed with a longitudinal hollow (not shown in detail) along which the bridle 32 extends when normally hanging from the cross member 30. Displacement of the skip 10 in the outward direction of arrow 76 is achieved in response to the rollers 72 coming in guiding engagement with a guide formation 78 forming a fixture at the skip discharge zone. This is normally at the upper end of a shaft along which the skip is displaceable. The formation 78 is thus engaged from below by the rollers 72 on the skip reaching the discharge zone along the shaft. The formation 78 is formed with a gradual outward curve 78.1 in the direction of causing skip pendulous displacement (the outward direction of arrow 76) thus causing such displacement once the skip rollers 72 pass into the curved section of the guide formation 78.

The operation of the cam and follower arrangement 74 in opening and closing the door 28 ties in with the pendulous swivelling of the skip 10. To this end the door 28 is swivellably mounted along its one side via a hinge 80. The cam and follower arrangement 74 comprises a cam pair 82 fitted to the bottom end of the bridle 32 that runs upward and inward from outer lips 82.1 while the upper end of each cam path ends in a cam saddle 84 accessible along a cam knob 86 that limits undesired escape of a follower from the cam saddle 84 except when positively so urged. The arrangement 74 thus also comprises a cam follower for each cam 82 in the form of a cam roller 88 fitted at a suitable position below the door 28 to cause its opening and closing swivelling in response to roller to cam engagement. Firm closure of the door 28 is maintained (as shown in figure 10(a)) once the rollers 88 have moved into their cam saddles 84 while undesired opening of the door 28 is counteracted owing to the cam knobs 86 limiting escape of the rollers 88. Once the rollers 72 commence engagement with the guide formation 78 on upward displacement of the skip 10, it is gradually urged to pendulously swivel in the outward direction of arrow 76. This has the effect of urging each roller 88 from its saddle 84 past the knob 86 along the downward part of its cam path 82 causing the progressive opening of the door 28. Although the skip 10 is in upward motion at such time the cam paths 82 extend at suitable slopes to achieve such door opening effect. Once the guide engaging rollers 72 have been guided past the outward curve 78.1 along the guide formation 78 the door 28 is swivelled to its fully open condition as shown in figure 10(c). In this position the cam rollers 88 are just short of their cam lips 82.1. Closure of the door 28 naturally involves a reverse of the opening procedure. It will be appreciated that the skip 10 need not be fitted with the opening and closing mechanism 70.

Manufacturing of the skip naturally commences with manufacturing of the skip body 12. The rib formations 20 are subsequently fitted to the body 12. This can be done by either fully pre- manufacturing the rib formations 20 and then welding them to the inner wall of the skip body 12. Otherwise the rib formations 20 can be formed in the process of securing the various parts making up the formations 20 inside the skip body 12. In whichever way formed the liners 62, when so arranged, and the buffers 64 are naturally fitted to the skip body 12 once the rib formations 20 are operatively installed. It is an advantage of the invention as specifically described that a zones of reduced skip wall endurance, as brought about by the welding of strengthening ribs to the skip body, are caused to extend along the flexing plane of the skip body side wall thereby reducing their contribution to metal fatigue in response to use of the skip. A further advantage is found in locating any welds whether along the skip body as such or between the various sections of strengthening formations, that tend to be exposed to bending stresses during use of the skip, to lie in or in the vicinity of the regions of skip wall contra flexure consequently reducing bending stresses there along.

The overall effect of the above two advantages is that the regions of higher stress along the skip wall is free of any welds that will otherwise tend to reduce its endurance.

Yet a further advantage is that the location of the rib formations along the inner wall of the skip body has the effect of more effectively using the cross sectional area of a shaft. It will, however, be appreciated that the invention also extends to a skip of which the strengthening formations are situated along the outside wall if the skip body.

Claims

(5) CLAIMS

(1 ) A method of strengthening an enclosed load carrier (10) conventionally being formed with planar side walls that are exposed to outwardly urging load forces during operative use of the carrier and presenting a high elevational load charging opening (24) and an appropriately re- openably closable low elevational discharge opening (26) while being fitted to be conventionally displaced and in use being constrained to be displaced along a vertical guide path of complementary cross sectional area as thus determining the shape of the carrier comprising integrally fitting the body (12) of the carrier with a carrier body sidewall outward displacement limiting and strengthening rib formation layout comprising at least one rib formation (20); characterised in that the at least one rib formation (20) is secured to extend circumferentially through the corners and along the side walls of the body (12) of the carrier about its central axis (22) as regards its direction of travel once in use, once secured, and in a way that results in its becoming secured to the wall of the carrier along at least one strip of integral securing that also extends circumferentially relative to the direction of displacement of the carrier body once fitted.

(2) A method as claimed in claim 1 that comprises fitting a plurality of adjacent rib formations (20) in a way that causes each to extend in a plane at least substantially transverse to the central axis (22) of the carrier. (3) A method as claimed in claim 2 that comprises forming the rib formations (20), as each constituted from a number of corner sections (40) equal to the number of corners formed between the side walls of the carrier with each corner section being formed to snugly fit and extend around a carrier body corner, and a number of linear sections (42) to the extent of linking the corner sections, by integrally end on securing the linear sections (42) to opposite corner sections (40) with each rib formation at the latest becoming fully formed once the linear sections (42) are end on secured to the corner sections (40) , as pre-secured to the carrier body (12), and to the carrier body, or vice versa, if not already fully pre-formed and as a unit integrally fitted to the body of the carrier, the linear sections being lengthwise dimensioned and the corner sections formed to extend to an adequate extent along adjacent side walls of the carrier body to result in their locations of inter-securing being situated in the vicinity of the zones of contra flexure of the side walls of the carrier body once the rib formations are so operatively secured. (4) A method as claimed in claim 3 that comprises end on securing the linear sections (42) and the corner sections (40), as appropriately matchingly formed, along at least part of contiguously extending facing end edges.

(5) A method as claimed in claims 4 that comprises, in the case where the linear and corner sections are matchingly hollow, integrally strip fashion securing the various linear and corner sections (42, 40) along their opposite carrier body contiguously lying edges to the carrier

(6) A method as claimed in claim 5 that comprises also securing the corner sections (40) to the carrier body (12) via at least one intermediate strengthening rib (40.2) extending along the curvature of and extending intermediate the opposite edges of its corner section, to the carrier body.

(7) A method as claimed in any one of claims 2 to 6 that comprises securing at least the majority of the rib formations (20) along the inside wall of the carrier body.

(8) A method as claimed in claim 7 that comprises forming the rib formations (20) with oblique overhead sections (60) that slant inward and downward once the rib formations are installed to promote the unobstructed flow of particulate material within the carrier once in use.

(9) A method as claimed in claim 8 that at the latest during final installation of the rib formations (20) comprises lining their oblique overhead sections to protect them against abrasion. (10) A method as claimed in claim 9 that comprises covering at least those parts of the rib formations that are exposed to extensive charging impact on charging of the carrier with resilient buffers (64).

(11) A method as claimed in anyone of the preceding claims that involves the integral fitting of the rib formations (20) to the carrier body (12) by way of seam welding. (12) An enclosed load transporting carrier employable for transferring a load that has the effect of exerting an outward force on the side walls of the carrier during its operative use comprising a carrier body (12) that is formed with planar side walls (16) extending between carrier body corners (18) that are not necessarily discontinuously formed and that in conjunction with overhead and floor walls define a loading zone (14) extending between a high elevational load charging opening (24) and an appropriately re-openably closable low elevational discharge opening (26) with the carrier body being fitted to be connected for conventional displacement along a vertical guide path extending between generally planar side walls to which the end profile of carrier body is matched, and a carrier body sidewall outward displacement limiting and strengthening rib formation layout comprising at least one rib formation (20); characterised in that the at least one rib formation (20) extends circumferentially through the corners and along the side walls of the body (12) of the carrier about its central axis (22) as regards its direction of travel once in use, while being secured to the walls of the carrier along at least one strip of integral securing that also extends circumferentially relative to the direction of displacement of the carrier body (12) if not via intermittent securing strips. (13) A load transporting carrier as claimed in claim 12 in which the carrier body (12) is constituted from panels (34) and corner formations (38) as integrally secured to one another at positions spaced from the corner axes of the carrier body to limit carrier body corner stresses once operatively used under conditions of load.

(14) A load transporting carrier as claimed in claim 13 in which the panels and corner formations (34, 38) are dimensioned to cause their locations of inter-securing to lie in the region of the zones of contra flexure of the walls of the carrier body.

(15) A load transporting carrier as claimed in claim 13 or claim 14 in which the radii of the carrier corner formations are each in the order of the ten times the thickness of the wall of the carrier body. (16) A load transporting carrier as claimed in any one of claims 12 to 15 in which the rib formation layout is in the form of a plurality of integrally secured rib formations (20) that extend adjacent one another with each extending in a plane at least substantially transverse to the central axis (22)of the carrier body.

(17) A load transporting carrier as claimed in claims 16 in which each rib formation (20) is constituted from a number of corner sections (40) equal to the number of corners formed between the side walls of the carrier body with each corner section snugly fitting and extending through a carrier body corner, and a number of linear sections (42) that are end on secured to opposite corner sections, the linear sections being lengthwise dimensioned and the corner sections formed to extend to an adequate extent along the adjacent panels to result in their locations of inter-securing to be situated in the vicinity of the zones of contra flexure of the side walls of the carrier body. (18) A load transporting carrier as claimed in anyone of claims 17 in which the corner sections and the linear sections (40, 42) are integrally secured to the carrier body along strips of securing in the form of longitudinal seam welds.

(19) A load transporting carrier as claimed in claim 17 or claim 18 in which the corner and linear sections (40, 42) extend in the form of matchingly end profiled cavitateous interior defining formations each encompassing in conjunction with the carrier wall a hollow zone extending between corner and linear section ends respectively with the formations (20) being secured to the carrier wall along opposite parallel edges and to one another along contiguously extending facing end edges. (20) A load transporting carrier as claimed in claim 19 in which each corner section (40) is also secured to the carrier body (12) via at least one strengthening rib (40.2) extending intermediate its parallel opposite edges.

(21 ) A load transporting carrier as claimed in claim 19 or claim 20 in which the linear sections and the corner sections (42, 40) are channel shaped with the latter extending through the corners of the carrier wall.

(22) A load transporting carrier as claimed in any one of claims 18 to 21 in which the corners of the carrier body are arcuately formed with the corner sections (40) being complementary arcuately formed to snugly fit the corners of the carrier body (12), the at least one strengthening rib (40.2) of each corner section (40) when so fitted and consequently presenting a hollow interior zone, thus following the curvature of its corner section (40).

(23) A load transporting carrier as claimed in claim 22 in which the inner radius (52) of each corner section (40) when channel shaped, is at least generally of the same order of magnitude as its outer radius (50) causing the depth (54) of the corner sections to progressively increase in the direction of their transverse centre lines. (24) A load transporting carrier as claimed in any one of claims 17 to 23 in which at least the majority of rib formations (20) are secured along the inside of the carrier body (12).

(25) A load transporting carrier as claimed in any one of claims 17 to 24 in which the rib formations (20) in the case of being prone to obstruct the flow of particulate material charged to the carrier, are fitted with oblique overhead deflectors (60) that slant inward and downward to limit such blocking effect once the carrier as operatively installed is in use.

(26) A load transporting carrier as claimed in 25 in which the oblique overhead deflectors (60) are lined to protect them against abrasion. (27) A load transporting carrier as claimed in claim 26 in which at least the parts of the rib formations that are exposed to extensive carrier charging impact are fitted with resilient impact absorbing buffers (64) that overhang the oblique overhead deflectors (60).

(28) A load transporting carrier as claimed in anyone of claims 12 to 27 that is generally rectangular in cross section for snugly fitting a rectangular guide path.

(29) A load transporting carrier as claimed in anyone of claims 12 to 28 that is in the form of a mining skip for use along a mining shaft.

(30) A load transporting carrier as claimed in anyone of claims 12 to 29 in which the re- openably closable low elevational discharge opening (26) is reopenably closable by a downwardly openable door (28) hinged along one side and that is operable by a opening and closing mechanism (70) that promotes the smooth opening of the door (28) in response to pendulous sideward displacement of the carrier body (12) as appropriate suspended and vice versa while limiting the possibility of inadvertent door opening once in its closed condition.

(31 ) A load transporting carrier as claimed in claim 30 in which the opening and closing mechanism (70) incorporates a cam and follower layout (74) associated, on the one hand, with the door (28) and, on the other hand, with a non-sideward displaceable carrier body support (32) with the cam (82) of the layout being formed with a saddle (84) into which the follower (88) becomes positioned once the door (28) is closed while release from the saddle (84) requires the exertion of force as brought about by the commencement of sideward displacement of the carrier body during operative use of the carrier (10), progression of which sideward displacement having the effect of the cam (82) moving along the follower (88) in a way that causes progressive opening of the door (28).

(32) A load transporting carrier as claimed in claim 31 in which the cam (82), as secured to the non-sideward displaceable carrier body support (32), runs downward at a suitable slope past a hump (86) from the high elevation cam saddle (84) while the follower (88) is suitably associated with the door (28), sideward displacement of the carrier body (12) thus urging the follower (88) from the saddle (84) and past the hump (86) with displacement down the cam (82) causing the progressive opening of the door(28).

(33) A load transporting carrier as claimed in claim 32 in which the carrier body (12) is fitted with a guide path coupler (72) that comes into engagement with guide path defining means

(78), not forming part of the carrier, that is appropriately situated at the location of carrier discharge along its path of displacement and formed to cause progressive pendulous sideward swivelling of the carrier body (12) on engagement of the coupler (72) with the guide path defining means (78) during operative use of the carrier.